Wednesday, February 26, 2014

Alternator Wiring Harness

Here's my Subaru/Vanagon alternator harness design.  The main RMW wiring harness does not include the ALT, starter, fuel pump, A/C compressor, voltage sensor or coolant level sensor!  So, I had to create my own sub-harness for these and figure out how to integrate them into the VW and main wiring harness.  This took a lot of brain cycles, hence my posting here to help others in the same predicament.

I am looking for a better way to do my wiring harness, in general, to make it a more turn-key install rather than two separate harnesses like this.  I'll keep you posted!

EDIT April 16, 2014: 
With the new decision to place my Subaru ECU in the rear passenger tail light, I can combine this sub-harness described here directly into the main Subaru harness.  What does this mean to my original design here?  For one, the fuel pump wire is shorter and directly connected to the ECU and their is no need to have the extra "pluggable" connectors since the wiring will be one main harness rather than the two.   Since it is now one, single harness, it all goes into the black box in a single location, so no need to mess with the extra black box grommet.

For more info, see my new solution here:  
subaru-ecu-placement-rear-passenger



A sub-harness is required when integrating a RMW wiring harness because it does not include these components

2 comments:

Unknown said...

Hi Jason, I am in the middle of connecting my ALT harness I need to know what wires in the green Subaru ALT connector you use for the ALT Light and Voltage signal and on the voltage signal wire where do you connect that in the van? Hope I am making sense and you can help me out. Thank you -Michael-

Jason said...

Hi Michael,

The Voltage Sense wire was changed from this diagram to simply loop back on itself. See this video here at 4:25:

https://www.youtube.com/watch?v=wDxldbQIISw

I also just checked my Rocky Mtn Westy manual and I believe it says a Yellow Subaru ALT wire connects to the Blue VW ALT wire. That said, I'd recommend getting a Subaru Repair Manual for your year and model to figure out what wires the ALT and Voltage Sense are for your conversion.